Preservative process for vegetable fibers



Patented June 7,1938 a r I 2,119,525

UNITED STATES PATENT OFFICE PRESEBVATIVE PROCESS FOR. VEGETABLE FIBERS Wallace '1. Conn, Lawrence, Mass, assignor to the Government of the United States, represented by the Secretary of Commerce No Drawing. Application December 12, 1933,

1 Serial No. 102,033

1 Claim. (01. 21-4) (Granted under the act of March '3, 1883, as amended April 30, 1928; 370 0. G. 75'l) The invention described herein may be manusolution of an oxidizing agent, substantially dryfactured and used by or for the Government of ing the material, and immersing the dried matethe United States for governmental purposes rial in heated tar. without the payment to me of any royalty thereon. In other words, my invention consists in tan- My invention relates to the preservation of 'ning the fibrous material, applying, an after 5 vegetable fibers, cordage, thread, or net, 'for the treatment, substantially drying the same, and purpose of prolonging the service life thereof, then applying a cover or armor. especially when subjected to varying weather After years of study and experimentation 1 conditions or submerged in water. The invenhave successfully accomplished distinct improvetion-also relates to the preservation of the prodments in solving the problems suggested in the 10 ucts thus treated, and the ingredients for treating publications heretofore discussed, and I have apsuch products plied my method of preservation to commercial More specifically, my invention relates to comfish nets in which equal benefits have been probining, in vegetable fibers, chemical and bacteriduced. cidal preservatives, such as catechu, cutch, quer- The following is one practical form of the 15 eitron, or other similar tanning materials, with process. Number 6 hard laid cable cotton thread a mechanical armoring or waterproofing cover, has been tanned by soaking in an approximately and impregnating the fibers with a composition of 6% catechu extract aqueous solution (or 3% a ta -dik ubstan e, quercitron aqueous solution) at a simmering heat The tanning or barking of fish nets for the of approximately 210 Fahrenheit preferably for o purpose of preservation is perhaps as old as the approximately twelve hours, then boiling the unuse of vegetable fibers for nets and today is washed thread for approximately 15 minutes in practiced with various modifications in many an approximately /z% aqueous solution of poparts of the world. It is only within recent tassium dichromate, followed by thorough rinstimes, however, that the efficacy of this prin- 'ing in clear water and drying. The dried tanned ciple of preservation has been recognized as a thread was then immersed in coal tar for apresistance imparted to the fiber which retards diproximate y 3 minutes ata tempera of pgestion of the cellulose by bacteria. Perhaps the proximately 200 Fahrenheit, drained and dried. most valuable and certainly the most stable pro- A coal tar found to give satisfactoryresults is tective property of tars on fish nets is the impartfrequently known as Fisheries specification coal ed resistance to mechanical abrasion which is tar and consists of tar prepared within them]- comparable to armoring or sheathing. My melowing specification: chamcally efficient cover, even in case of loss of Specific gravity at C. F.) 1104.14

certain chemical con'stitutents, continues to proo o tect a relatively delicate inclosed material and also speclfic Y at Q 4 p 35 will materially retard solution or other changes "T". in the composition of the inclosed material. f ,'fg igg B g f g m n 7 t Heretofore it has been proposed to apply a combi- F t m per nation of catechu and tar treatment to fish nets. 42 per A suggestion for such an application of catechu ore an per cen I I 0 and tar may be found in .Bevaring of Garn, Bitumen Somme m carbon g g g her cent Norsk Fisheritideude, vol. V, No. 2. Bergen, April, T 1886, which has been translated by Harden F. gif s? Nmlessthan Per Taylor in United States Fisheries Document 898. not over per 45 My invention is an improved methodof treating By this method vegetable fibers will be found 45 vegetable fibers which are to be subjectedto clito retain and in fact gain in tensile strength for matic and atmospheric changes, and has distinct a long period of use in salt and fresh fishing advantages over that disclosed in these prior pubwaters. To my knowledge, the tensile strength lications and further is such a process as can be is greater after a 6 months period of constant use utilized for treating such fibers on a large comin fishing waters of the most destructive nature 50 mercial scale. to vegetable fibers to be found generally in lakes,

Broadly speaking, my invention consists in oceans, bays and rivers. Similar thread treated soaking vegetable fibers, cordage, thread or nets with the catechu only or the tar only disintegrated in a heated aqueous solution of a tanning agent, under adverse conditions within three weeks. boiling the treated fibrous material in an aqueous I believe that the benefit of my combination of 55 chemical and tar treatment is due to upsetting or alteration'of the natural food of cellulose digesting bacteria, thus rendering the fiber resistant to bacterial digestion by a chemical change in the composition of the fiber treated, and maintenance of this altered fiber composition over a relatively long period bythe tar cover or sheathing.

It will be apparent from the foregoing, that by my invention the armoring and waterproofing eflects of the tar conserve the bactericidal eiIect' 4 of the catechu.

It will be understood that the foregoing description of preservation applied to fish nets and twine is not to be limited to any specific method of tanning or cutching vegetable vfibers, thread, cordage or nets when covered with a tar-like substance, nor is my invention limited to any specific tar used to impregnate or cover tanned or cutched What I claim is:

The art of preserving cordage comprising the soaking thereoi in an aqueous solution of approximately 6% of catechu extract at approximately 210 Fahrenheit heat for approximately twelve hours, boiling the material for approximately 15 minutes in an aqueous solution of approximately of potassium dichromate, rinsing in water and drying the material thus treated, and there- 'materials of the class described except asindirated in the claim. 1 z .a 1 v after immersing the dried material for approxh mately 3 minutes in coal tar at a temperature of approximately 200? Fahrenheit.

WAILACE T. CONN. 

